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Re: [Xen-devel] [PATCH] compile with -funit-at-a-time option of gcc

To: "Ian Pratt" <m+Ian.Pratt@xxxxxxxxxxxx>
Subject: Re: [Xen-devel] [PATCH] compile with -funit-at-a-time option of gcc
From: Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>
Date: Thu, 30 Jun 2005 09:04:42 +0100
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On 30 Jun 2005, at 08:21, Ian Pratt wrote:

This patch makes xen compiled with gcc option
-funit-at-a-time if supported. This option is available for
gcc 3.4 and upward, which reduces the .text binary size considerably.

I haven't come across this option before. What does it actually do?

Considers whole file at a time when doing optimisation. It's the default on gcc4 with -O2 and above. We probably don;t want to enable it before a general move to gcc4 as it does break stuff (albeit stuff that was buggy/broken already ;-) ). Adding another skanky CFLAG that will be defaulted anyway in future, to get the benefit of maybe subtly breaking Xen, doesn;t sound like a big win to me.

 -- Keir

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